Merge branch 'ms/subtree-install-fix'

* ms/subtree-install-fix:
  contrib/subtree: Fix make install target

contrib/subtree/Makefile

@@ -30,6 +30,7 @@ $(GIT_SUBTREE): $(GIT_SUBTREE_SH)
 doc: $(GIT_SUBTREE_DOC)
 
 install: $(GIT_SUBTREE)
+	$(INSTALL) -d -m 755 $(DESTDIR)$(libexecdir)
 	$(INSTALL) -m 755 $(GIT_SUBTREE) $(DESTDIR)$(libexecdir)
 
 install-doc: install-man